by Carl Strang
Recently I noticed a patch of sun dapples on the trail, and was reminded of a surprising observation from a decade or two ago.
There was a mid-day eclipse of the sun that day, not total but the moon covered a significant percentage. I happened to be where there were patches of sun dapples like these, and as the eclipse progressed I was amazed to see the dapples changing shape. They all were images of the eclipse, at the peak showing little crescent suns.
Warnings had been broadcast in advance of the event, reminding people not to look directly at the eclipse, but to create a pinhole camera effect, holding two sheets of white cardboard, the one closer to the sun with a pinhole in it. The image of the eclipse would be formed on the back sheet, and could be sharpened by changing the distance between sheets. I realized that the tiny spaces between the leaves in the tree canopy above were, in effect, tiny pinholes, and the ground was covered by myriad images of the eclipse. The ground was not the correct distance from the canopy to produce sharp images, but they were clear enough to show the effect. The implication is that these dapples always are giving us images of the sun, as in the photo above.